Referring to FIG. 1, a conventional miniature-USB electrical connector 10a is secured to a circuit board 20a. In order to reduce the height of the electrical connector 10a, an opening 21a is generally formed in the circuit board 20a so that the electrical connector 10a can be received in the opening 21a so as to reduce the height of the electrical connector 10a projecting from the upper surface of the circuit board 20a. Such is a sunken plate type design.
Left and right sides of an outer housing 11a of the electrical connector 10a are respectively punched to form wings 12a. In addition, two solder plates 22a corresponding to the wings 12a are fixedly provided on the upper surface of the circuit board 20a. The two wings 12a lap the two solder plates 22a, and solder paste is applied between the two wings 12a and the two solder plates 22a so that the electrical connector 10a can be secured onto the circuit board 20a via soldering.
Referring to FIG. 2, the wings 12a on two sides of the outer housing 11a of the electrical connector 10a can also be provided with a through hole 13a for enhancing the solder securing effect so that the securing force between the two wings 12a and the two solder plates 22a can be increased.
However, in the aforesaid conventional electrical connector 10a, as the two sides of the outer housing 11a are soldered and secured to the upper surface of the circuit board 20a merely by the wings 12a, there is the problem of unsatisfactory positioning effect, so that the electrical connector 10a cannot be positioned on the circuit board 20a firmly, is likely to vibrate, and cannot endure plugging and unplugging operations during insertion and removal thereof, which may lead to loosening or disengagement between the electrical connector 10a and the circuit board 20a. 
Therefore, it can be seen from the above that the electrical connector and circuit board securing structure clearly is inconvenient and has drawbacks in actual use, and needs to be improved.
Accordingly, the inventor, believing that there are ways to eliminate the drawbacks, indulged in researches and employed theoretical principles, finally proposed this invention which is a reasonable design that can effectively overcome the drawbacks.